There is an urgent need to develop novel therapies for patients with highly malignant uveal melanomas in the eye. Patients with uveal melanoma die within 1-2 years of diagnosis despite current conventional therapies, including eye enucleation, brachotherapy and chemotherapy. Hypoxia drives tumor progression by activating angiogenesis, cell motility and metastasis, as well as metabolic adaptation to growth under a hypoxic environment and is a major factor in the resistance of cancer cells to radio- and chemotherapies. Hypoxia activates transcription factors of the Hypoxia-Inducible Factor (HIF) family that induce the expression of genes that encode pro-angiogenic factors and glycolytic enzymes essential for tumor growth and favor tumor invasion. Based on these findings, we formulated the central hypothesis that development of hypoxia and activation of the HIF pathway play a critical role in ocular cancer growth and spread, and that therapeutic targeting of this pathway using small molecule inhibitors will inhibit ocular tumor growth and metastasis. We have generated substantial preliminary data validating this concept. We show that our lead probe (KCN1) is a potent inhibitor of the in vivo growth of uveal melanoma in the eye (70% tumor size reduction) and its metastasis to the liver (50% reduction in number of metastases), while being extremely well tolerated. The overall goals of this proposal are to refine the structur of the novel HIF pathway inhibitor (HPI) chemical probes we developed, optimize their potency and pharmacological properties, leading to the identification of 1- 2 clinical lead probes that wil be ready to undergo IND-directed pharmacology and toxicology towards phase 1 clinical testing in patients with malignant uveal melanoma through the NCI NExT program. Our multi- disciplinary team has expertise in major aspects of chemical probe development and will divide the project tasks into the following aims: screening analogs of the parent compound in primary and secondary assays to identify and confirm chemical probes with improved potency and solubility (Aim 1); screening analogs of the optimized probes for improved pharmacology and formulation development (Aim 2); and determine the anti- tumor efficacy of the optimized lead probe(s) in orthotopic uveal melanoma models in mice (Aim 3).